SUMMARY The broad, long-term goal of this project is to develop a pritelivir intravaginal ring (IVR) for the treatment and pre-exposure prophylaxis of genital herpes, a common problem that affects more than 50 million Americans. Recurrences are common and may be painful. Infection is life-long. Pritelivir is a promising ?-helicase inhibitor that proved superior to existing therapies in Phase 2 clinical trials, but whose clinical development as a systemic therapy has been arrested because of toxicity. Local therapy is therefore, of special interest. We have developed a platform technology for the sustained release of antivirals. This technology led to the FDA approval of a ganciclovir-based intraocular implant - Vitrasert, for the treatment of AIDS-related cytomegalovirus retinitis. We have adapted this platform to IVRs and have successfully delivered other antiviral agents at therapeutic levels in preclinical and clinical trials. We propose to utilize this platform to develop sustained release vaginal ring formulations for pritelivir. In this Phase I proposal, we will formulate pritelivir IVRs, test the formulations for in vitro release and perform safety and pharmacokinetic studies in an animal model, Successful completion of this work will lead to IND enabling studies in Phase II, and clinical trials in Phase IIB SBIR proposals. The team of investigators is expert in drug development, synthetic chemistry, pharmacokinetics, and clinical infectious disease. We have experience in collaboration with large pharmaceutical companies leading to the approval of novel drug delivery systems. This project could lead rapidly to the development of an improved treatment for genital herpes.